Service implementation method, apparatus, and system

ABSTRACT

A service implementation method, apparatus, and system are disclosed. The service implementation method includes: receiving, by a serving gateway, a data packet of a terminal device sent by a packet data network gateway; if the data packet is a data packet with a serving priority and the serving gateway has sent a paging trigger message with a serving priority to a mobility management element, skipping, by the serving gateway, sending a paging trigger message to the mobility management element; or if the data packet is a data packet with a serving priority and the serving gateway has sent no paging trigger message with a serving priority to a mobility management element, sending, by the serving gateway, a paging trigger message to the mobility management element; wherein the paging trigger message is used to enable the mobility management element to page the terminal device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Reissue Application of U.S. patent applicationSer. No. 14/474,744, filed on Sep. 2, 2014, now U.S. Pat. No. 9,661,606,which is a continuation of U.S. application Ser. No. 13/729,274, filedon Dec. 28, 2012, now U.S. Pat. No. 8,862,163, which is a continuationof International Application No. PCT/CN2010/074629, filed on Jun. 28,2010, The afore-mentioned patents all of which are hereby incorporatedby reference in their entireties.

FIELD OF THE INVENTION

The present invention relates to the field of network communicationstechnologies, and in particular to a service implementation method,apparatus, and system.

BACKGROUND OF THE INVENTION

When an emergent event or an urgent matter occurs, it is necessary toensure that a part of population (such as government workers,firefighters, police, and medical staff) has the priority to use networkresources. Even in the case of network congestion, it is also necessaryto ensure that this part of the population is capable of properly usingnetwork resources.

For an emergent event or an urgent matter, a 3GPP network provides asolution such as the Enhanced Multimedia Priority Service (EnhancedMultimedia Priority Service, eMPS) to ensure that the part of users suchas government workers, firefighters, or police who have the accesspriority is capable of properly using network resources in the case ofnetwork congestion. In the case of network congestion or the like, it isensured that a user with an eMPS capability has the priority to usenetwork resources. Certainly, in other network architecture, a solutionfor ensuring that the part of users with the access priority has thepriority to use network resources may also be called another name, whichis not limited herein.

An existing service implementation method cannot ensure that a user withan eMPS capability has the priority to use network resources. In anexisting service implementation process, after receiving a downlink datapacket of a User Equipment (user equipment, UE) sent by a Packet DataNetwork Gateway (packet data network gateway, P-GW), a Serving Gateway(serving gateway, S-GW) may trigger a mobility management element topage the UE, so as to deliver the downlink data packet to the UE. Themobility management element may be a Mobility Management Entity(mobility management entity, MME), a Serving GPRS Supporting Node(serving GPRS supporting node, SGSN), or the like.

To avoid that each downlink data packet of the UE received by the S-GWtriggers the mobility management element to page the UE, which bringspressure on an air interface, the S-GW may generally adopt thetechnology of periodically triggering the MME to page the UE or notrepeatedly triggering the MME to page the UE before the UE initiates aservice request. However, in a practical service implementation process,a UE without an eMPS capability may be transformed to have the eMPScapability or a UE with a low-priority eMPS capability may betransformed to have a high-priority eMPS capability. In this case, ifthe S-GW has triggered, for a previously received downlink data packetof the UE, the MME to perform paging, the S-GW will trigger the MME topage the UE when the next timing interval arrives or will not triggerthe MME to page the UE no matter whether a downlink data packet of theUE subsequently received by the S-GW is a downlink data packet of the UEwith the lower-priority eMPS capability or a downlink data packet of theUE with the higher-priority eMPS capability. As a result, the existingservice implementation method cannot ensure that a user with an eMPScapability has the priority to use network resources.

Similarly, after receiving the first paging trigger message of the UE,the mobility management element may page the UE through an accessnetwork element. After the mobility management element delivers a pagingmessage to the access network element and before the mobility managementelement receives a paging response message of the UE, the mobilitymanagement element will not page the UE for the latter received pagingtrigger message if the mobility management element receives anotherpaging trigger message of the UE. In this case, no matter whether thelatter paging trigger message received by the mobility managementelement requires a preferential paging service, the mobility managementelement will not page the UE for the paging trigger message. As aresult, the existing service implementation method cannot ensure that auser with an eMPS capability has the priority to use network resources.

SUMMARY OF THE INVENTION

A service implementation method, apparatus, and system provided inembodiments of the present invention are capable of ensuring that a userwith an eMPS capability has the priority to use network resources whileavoiding pressure brought to an air interface.

A service implementation method according to an embodiment of thepresent invention includes:

receiving, by a serving gateway, a data packet of a terminal device sentby a packet data network gateway; and

if the data packet is a data packet with a serving priority and theserving gateway has sent a paging trigger message with a servingpriority to a mobility management element, skipping, by the servinggateway, sending a paging trigger message to the mobility managementelement;

or

if the data packet is a data packet with a serving priority and theserving gateway has sent no paging trigger message with a servingpriority to a mobility management element, sending, by the servinggateway, a paging trigger message to the mobility management element;

where the paging trigger message is used to enable the mobilitymanagement element to page the terminal device.

Another service implementation method according to an embodiment of thepresent invention includes:

receiving, by a mobility management element, a paging trigger message ofa terminal device sent by a serving gateway; and

if the paging trigger message is a paging trigger message with a servingpriority and the mobility management element has sent a paging messagewith a serving priority to an access network element, skipping, by themobility management element, sending a paging message to the accessnetwork element; or

if the paging trigger message is a paging trigger message with a servingpriority and the mobility management element has sent no paging messagewith a serving priority to an access network element, sending, by themobility management element, a paging message to the access networkelement.

A service implementation apparatus according to an embodiment of thepresent invention includes:

a first receiving module, configured to receive a data packet of aterminal device sent by a packet data network gateway; and

a first control module, configured to skip sending a paging triggermessage to a mobility management element if the data packet is a datapacket with a serving priority and the service implementation apparatushas sent a paging trigger message with a serving priority to themobility management element; or

a first control module, configured to send a paging trigger message to amobility management element if the data packet is a data packet with aserving priority and the service implementation apparatus has sent nopaging trigger message with a serving priority to the mobilitymanagement element;

where the paging trigger message is used to enable the mobilitymanagement element to page the terminal device.

Another service implementation apparatus according to an embodiment ofthe present invention is a mobility management element and includes:

a second receiving module, configured to receive a paging triggermessage of a terminal device sent by a serving gateway; and

a second control module, configured to skip sending a paging message toan access network element if the paging trigger message is a pagingtrigger message with a serving priority and the service implementationapparatus has sent a paging message with a serving priority to theaccess network element; or

a second control module, configured to send a paging message to anaccess network element if the paging trigger message is a paging triggermessage with a serving priority and the service implementation apparatushas sent no paging message with a serving priority to the access networkelement.

A service implementation system according to an embodiment of thepresent invention includes a serving gateway and a mobility managementelement, where:

the serving gateway is configured to receive a data packet of a terminaldevice sent by a packet data network gateway and send a paging triggermessage to the mobility management element; and

the mobility management element is configured to receive the pagingtrigger message of the terminal device sent by the serving gateway, andif the paging trigger message is a paging trigger message with a servingpriority and the mobility management element has sent a paging messagewith a serving priority to an access network element, skip sending apaging message to the access network element; or if the paging triggermessage is a paging trigger message with a serving priority and themobility management element has sent no paging message with a servingpriority to an access network element, send a paging message to theaccess network element.

BRIEF DESCRIPTION OF THE DRAWINGS

To illustrate the technical solutions in the embodiments of the presentinvention or in the prior art more clearly, the following brieflydescribes the accompanying drawings required for describing theembodiments or the prior art. Apparently, the accompanying drawings inthe following descriptions merely show some embodiments of the presentinvention, and persons of ordinary skill in the art can derive otherdrawings from the accompanying drawings without creative efforts.

FIG. 1 is a flowchart of a service implementation method according toEmbodiment 1 of the present invention;

FIG. 2 is a flowchart of a service implementation method according toEmbodiment 2 of the present invention;

FIG. 3 is a flowchart of a service implementation method according toEmbodiment 3 of the present invention;

FIG. 4 is a flowchart of a service implementation method according toEmbodiment 4 of the present invention;

FIG. 5 is a flowchart of a service implementation method according toEmbodiment 5 of the present invention;

FIG. 6 is a flowchart of a service implementation method according toEmbodiment 6 of the present invention;

FIG. 7A is a schematic diagram of an application scenario according toEmbodiment 7 of the present invention;

FIG. 7B is a flowchart of a service implementation method according toEmbodiment 7 of the present invention;

FIG. 8 is a schematic diagram of a service implementation apparatusaccording to Embodiment 8 of the present invention;

FIG. 9 is a schematic diagram of a service implementation apparatusaccording to Embodiment 9 of the present invention;

FIG. 10 is a schematic diagram of a service implementation apparatusaccording to Embodiment 10 of the present invention;

FIG. 11 is a schematic diagram of a service implementation apparatusaccording to Embodiment 11 of the present invention; and

FIG. 12 is a schematic diagram of a service implementation apparatusaccording to Embodiment 12 of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The following embodiments describe the specific implementation processof the present invention with the help of examples. Obviously, theembodiments to be described below are only part of rather than all ofthe embodiments of the present invention. All other embodiments obtainedby persons of ordinary skill in the art based on the embodiments of thepresent invention without creative efforts shall fall within theprotection scope of the present invention.

Embodiment 1 provides a service implementation method. The method isdescribed below with reference to FIG. 1 .

As shown in FIG. 1 : S100. A serving gateway receives a data packet of aterminal device sent by a packet data network gateway.

The data packet of the terminal device sent by the packet data networkgateway and received by the serving gateway may also be named a downlinkdata packet. For ease of description, the name of downlink data packetis used in each of the following embodiments for description. Thedownlink data packet may be a user-plane data packet or controlsignaling. The control signaling may be, for example, a create bearerrequest, a create dedicated bearer request, or an update bearer request.Content specifically included in the downlink data packet, user-planedata packet, and control signaling of the terminal device is not limitedin this embodiment.

S110. If the downlink data packet is a downlink data packet with aserving priority and the serving gateway has sent a paging triggermessage with a serving priority to a mobility management element, theserving gateway skips delivering a paging trigger message to themobility management element. The paging trigger message is used toenable the mobility management element to page the terminal device. Thedelivered paging trigger message with a serving priority is a pagingtrigger message delivered for the downlink data packet with a servingpriority. In this embodiment of the present invention, delivering, bythe serving gateway, the paging trigger message with a serving priorityto the mobility management element is sending, by the serving gateway,the paging trigger message with a serving priority to the mobilitymanagement element. In this embodiment and other embodiments of thepresent invention, “delivering” mentioned in other places means sending.

S110 may be implemented by using “information about the sent pagingtrigger message with a serving priority”. A specific example is asfollows: If the serving gateway determines that the received downlinkdata packet is a downlink data packet with a serving priority and theserving gateway has recorded the “information about the sent pagingtrigger message with a serving priority”, the serving gateway skipsdelivering a paging trigger message to the mobility management element.Each paging trigger message described above is used to enable themobility management element to page the terminal device. The pagingtrigger message may specifically be a downlink data notification messageor control signaling. For example, when the downlink data packet is auser-plane data packet, the paging trigger message may specifically be adownlink data notification message. For another example, when thedownlink data packet is control signaling and the Idle Mode SignalingReduction (idle mode signaling reduction, ISR) is activated, the pagingtrigger message may specifically be a downlink data notificationmessage. For still another example, when the downlink data packet iscontrol signaling and the ISR is not activated, the paging triggermessage may specifically be control signaling. The specific name andspecific included content of the paging trigger message are not limitedin this embodiment.

In S110, there are multiple manners for the serving gateway to determinewhether the received downlink data packet is a downlink data packet witha serving priority. For example, when the downlink data packet receivedby the serving gateway is a user-plane data packet, the serving gatewaymay determine whether the received downlink data packet is a downlinkdata packet with a serving priority according to the allocation andretention priority (ARP) in the bearer quality of service (QoS) of theuser-plane data packet. For another example, when the downlink datapacket received by the serving gateway is control signaling, the servinggateway may determine whether the control signaling is a downlink datapacket with a serving priority according to a QoS parameter in thecontrol signaling. The specific implementation manner for the servinggateway to determine whether the received downlink data packet is adownlink data packet with a serving priority is not limited in thisembodiment.

The “information about the sent paging trigger message with a servingpriority” in S110 may be a “flag bit of sent downlink data with aserving priority”, “information about a priority with a servingpriority”, or a “flag bit of sent downlink data with a serving priority”and “information about a priority with a serving priority”. Certainly,the “information about the sent paging trigger message with a servingpriority” may also adopt another setting manner. The specificpresentation form of the “information about the sent paging triggermessage with a serving priority” is not limited in this embodiment.

The “flag bit of sent downlink data with a serving priority” may be a1-bit FLAG. For example, when no FLAG is set or a set FLAG is 0, itindicates that no downlink data with a serving priority has been sent;when a FLAG is set or a set FLAG is 1, it indicates that downlink datawith a serving priority has been sent.

When the “information about the sent paging trigger message with aserving priority” is a “flag bit of sent downlink data with a servingpriority”, an example of a specific implementation process of S110 is asfollows: The serving gateway determines whether the received downlinkdata packet is a downlink data packet with a serving priority andwhether the “flag bit of sent downlink data with a serving priority” isset. If the received downlink data packet is a downlink data packet witha serving priority and the “flag bit of sent downlink data with aserving priority” is set, the serving gateway skips delivering a pagingtrigger message to the mobility management element for the receiveddownlink data packet with a serving priority.

The example of the specific implementation process of S110 may also bedescribed as follows: If the downlink data packet with a servingpriority of the terminal device received by the serving gateway is notthe first received downlink data packet with a serving priority, theserving gateway skips delivering a paging trigger message to themobility management element.

When the “information about the sent paging trigger message with aserving priority” is “information about a priority with a servingpriority”, an example of a specific implementation process of S110 is asfollows: The serving gateway determines whether the received downlinkdata packet is a downlink data packet with a serving priority andwhether the “information about a priority with a serving priority” isset. If the received downlink data packet is a downlink data packet witha serving priority and the “information about a priority with a servingpriority” is set, the serving gateway determines whether the priority ofthe downlink data packet is higher than the priority indicated by theset “information about a priority with a serving priority”. If thepriority of the downlink data packet is not higher than the priorityindicated by the set “information about a priority with a servingpriority”, the serving gateway skips delivering a paging trigger messageto the mobility management element for the received downlink data packetwith a serving priority.

When the “information about the sent paging trigger message with aserving priority” is a “flag bit of sent downlink data with a servingpriority” and “information about a priority with a serving priority”, anexample of a specific implementation process of S110 is as follows: Theserving gateway determines whether the received downlink data packet isa downlink data packet with a serving priority and whether the “flag bitof sent downlink data with a serving priority” is set. If the receiveddownlink data packet is a downlink data packet with a serving priorityand the “flag bit of sent downlink data with a serving priority” is set,the serving gateway determines whether the priority of the downlink datapacket is higher than the priority indicated by the set “informationabout a priority with a serving priority”. If the priority of thedownlink data packet is not higher than the priority indicated by theset “information about a priority with a serving priority”, the servinggateway skips delivering a paging trigger message to the mobilitymanagement element for the received downlink data packet with a servingpriority. If the serving gateway determines that the received downlinkdata packet is not a downlink data packet with a serving priority, theserving gateway may adopt an existing processing manner to performpaging trigger control.

As can be seen from the description in Embodiment 1, after receiving adownlink data packet, the serving gateway in Embodiment 1 may determinewhether to skip delivering a paging trigger message to the mobilitymanagement element by determining whether the downlink data packet is adownlink data packet with a serving priority and whether a pagingtrigger message with a serving priority has been delivered to themobility management element. In this case, a paging trigger message isdelivered to the mobility management element only when the downlink datapacket is a downlink data packet with a serving priority and no pagingtrigger message with a serving priority has been delivered to themobility management element. In this way, even when the serving gatewayhas been in the state of being forbidden to deliver a paging triggermessage to the mobility management element to relieve pressure on an airinterface, the serving gateway is still capable of delivering a pagingtrigger message to the mobility management element for a downlink datapacket with a serving priority. The serving gateway delivers a pagingtrigger message to the mobility management element for a downlink datapacket with a serving priority. Therefore, pressure on an air interfaceis basically not increased in this embodiment. In this way, in thisembodiment, a user with an eMPS capability is enabled to be paged intime while the pressure on the air interface can be reduced, therebyensuring that the user with the eMPS capability has the priority to usenetwork resources.

Embodiment 2 provides a service implementation method. The method isdescribed below with reference to FIG. 2 .

As shown in FIG. 2 : S200. A serving gateway receives a downlink datapacket of a terminal device sent by a packet data network gateway.

The downlink data packet received by the serving gateway may be auser-plane data packet or control signaling. The control signaling maybe, for example, a create bearer request, a create dedicated bearerrequest, or an update bearer request. Content specifically included inthe downlink data packet, user-plane data packet, and control signalingof the terminal device is not limited in this embodiment.

S210. If the downlink data packet is a downlink data packet with aserving priority and the serving gateway has delivered no paging triggermessage with a serving priority to a mobility management element, theserving gateway delivers a paging trigger message to the mobilitymanagement element. The paging trigger message is used to enable themobility management element to page the terminal device.

Further, after sending the paging trigger message with a servingpriority to the mobility management element, the serving gateway records“information about the sent paging trigger message with a servingpriority”.

A specific example of S210 is as follows: If the serving gatewaydetermines that the received downlink data packet is a downlink datapacket with a serving priority and the serving gateway does not recordthe “information about the sent paging trigger message with a servingpriority”, the serving gateway delivers a paging trigger message to themobility management element and records the “information about the sentpaging trigger message with a serving priority”. The paging triggermessage delivered by the serving gateway to the mobility managemententity may specifically be a downlink data notification message orcontrol signaling. For example, when the downlink data packet is auser-plane data packet, the paging trigger message may specifically be adownlink data notification message. For another example, when thedownlink data packet is control signaling and the ISR is activated, thepaging trigger message may specifically be a downlink data notificationmessage. For still another example, when the downlink data packet iscontrol signaling and the ISR is not activated, the paging triggermessage may specifically be control signaling. The specific name andspecific included content of the paging trigger message are not limitedin this embodiment.

In S210, there are multiple manners for the serving gateway to determinewhether the received downlink data packet is a downlink data packet witha serving priority. For example, when the downlink data packet receivedby the serving gateway is a user-plane data packet, the serving gatewaymay determine whether the received downlink data packet is a downlinkdata packet with a serving priority according to the allocation andretention priority (ARP) in the bearer quality of service (QoS) of theuser-plane data packet. For another example, when the downlink datapacket received by the serving gateway is control signaling, the servinggateway may determine whether the control signaling is a downlink datapacket with a serving priority according to a QoS parameter in thecontrol signaling. The specific implementation manner for the servinggateway to determine whether the received downlink data packet is adownlink data packet with a serving priority is not limited in thisembodiment.

The “information about the sent paging trigger message with a servingpriority” in S210 may be a “flag bit of sent downlink data with aserving priority”, “information about a priority with a servingpriority”, or a “flag bit of sent downlink data with a serving priority”and “information about a priority with a serving priority”. Certainly,the “information about the sent paging trigger message with a servingpriority” may also adopt another setting manner. The specificpresentation form of the “information about the sent paging triggermessage with a serving priority” is not limited in this embodiment.

The “flag bit of sent downlink data with a serving priority” may be a1-bit FLAG. For example, when no FLAG is set or a set FLAG is 0, itindicates that no downlink data with a serving priority has been sent;when a FLAG is set or a set FLAG is 1, it indicates that downlink datawith a serving priority has been sent.

When the “information about the sent paging trigger message with aserving priority” is a “flag bit of sent downlink data with a servingpriority”, an example of a specific implementation process of S210 is asfollows: The serving gateway determines whether the received downlinkdata packet is a downlink data packet with a serving priority andwhether the “flag bit of sent downlink data with a serving priority” isset. If the received downlink data packet is a downlink data packet witha serving priority and the “flag bit of sent downlink data with aserving priority” is not set, the serving gateway delivers a pagingtrigger message to the mobility management element and sets the “flagbit of sent downlink data with a serving priority”.

The example of the specific implementation process of S210 may also bedescribed as follows: If the serving gateway receives a downlink datapacket with a serving priority of the terminal device for the firsttime, the serving gateway delivers a paging trigger message to themobility management element and records the “flag bit of sent downlinkdata with a serving priority”.

When the “information about the sent paging trigger message with aserving priority” is “information about a priority with a servingpriority”, an example of a specific implementation process of S210 is asfollows: The serving gateway determines whether the received downlinkdata packet is a downlink data packet with a serving priority andwhether the “information about a priority with a serving priority” isset. If the received downlink data packet is a downlink data packet witha serving priority and the “information about a priority with a servingpriority” is set, the serving gateway determines whether the priority ofthe downlink data packet is higher than the priority indicated by theset “information about a priority with a serving priority”. If thepriority of the downlink data packet is higher than the priorityindicated by the set “information about a priority with a servingpriority”, the serving gateway delivers a paging trigger message to themobility management element for the received downlink data packet with aserving priority and sets the “information about a priority with aserving priority” according to the priority of the downlink data packet.If the received downlink data packet is a downlink data packet with aserving priority and the “information about a priority with a servingpriority” is not set, the serving gateway delivers a paging triggermessage to the mobility management element for the received downlinkdata packet with a serving priority and sets the “information about apriority with a serving priority” according to the priority of thedownlink data packet.

When the “information about the sent paging trigger message with aserving priority” is a “flag bit of sent downlink data with a servingpriority” and “information about a priority with a serving priority”, anexample of a specific implementation process of S210 is as follows: Theserving gateway determines whether the received downlink data packet isa downlink data packet with a serving priority and whether the “flag bitof sent downlink data with a serving priority” is set. If the receiveddownlink data packet is a downlink data packet with a serving priorityand the “flag bit of sent downlink data with a serving priority” is notset, the serving gateway delivers a paging trigger message to themobility management element for the received downlink data packet with aserving priority, sets the “flag bit of sent downlink data with aserving priority”, and sets the “information about a priority with aserving priority” according to the priority of the downlink data packet.If the received downlink data packet is a downlink data packet with aserving priority and the “flag bit of sent downlink data with a servingpriority” is set, the serving gateway determines whether the priority ofthe downlink data packet is higher than the priority indicated by theset “information about a priority with a serving priority”. If thepriority of the downlink data packet is higher than the priorityindicated by the set “information about a priority with a servingpriority”, the serving gateway delivers a paging trigger message to themobility management element for the received downlink data packet with aserving priority and sets the “information about a priority with aserving priority” according to the priority of the downlink data packet.

In this embodiment, the paging trigger message delivered by the servinggateway to the mobility management element may include information abouta serving priority, where the information about a serving priority mayenable the mobility management element to preferentially page theterminal device. The information about a serving priority in the pagingtrigger message may include: a flag bit with a serving priority and/orinformation about a priority with a serving priority. The contentspecifically included in the information about a serving priority in thepaging trigger message is not limited in this embodiment.

The mobility management element in this embodiment may include an MMEand/or an SGSN. For example, in an application scenario in which the ISRis not activated, the serving gateway may deliver a paging triggermessage to the MME or the SGSN according to an access technology adoptedby the terminal device, whereas in an application scenario in which theISR is activated, the serving gateway may deliver a paging triggermessage to the MME and the SGSN each.

As can be seen from the description in Embodiment 2, after receiving adownlink data packet, the serving gateway in Embodiment 2 may determinewhether it is necessary to deliver a paging trigger message again to themobility management element by determining whether the downlink datapacket is a downlink data packet with a serving priority and whether apaging trigger message has been delivered to the mobility managementelement for the downlink data packet. In this way, even when the servinggateway has been in the state of being forbidden to deliver a pagingtrigger message to the mobility management element to relieve pressureon an air interface, the serving gateway is still capable of deliveringa paging trigger message to the mobility management element for adownlink data packet with a serving priority. The serving gatewaydelivers a paging trigger message to the mobility management element fora downlink data packet with a serving priority. Therefore, pressure onan air interface is basically not increased in this embodiment. In thisway, in this embodiment, a user with an eMPS capability is enabled to bepaged in time while the pressure on the air interface can be reduced,thereby ensuring that the user with the eMPS capability has the priorityto use network resources.

Embodiment 3 provides a service implementation method. The method isdescribed below with reference to FIG. 3 .

As shown in FIG. 3 : S300. A serving gateway receives a downlink datapacket of a terminal device sent by a packet data network gateway.

S310. If the downlink data packet is a downlink data packet with aserving priority and the serving gateway has delivered a paging triggermessage with a serving priority to a mobility management element, theserving gateway skips delivering a paging trigger message to themobility management element; or if the serving gateway determines thatthe received downlink data packet is a downlink data packet with aserving priority and the serving gateway has delivered no paging triggermessage with a serving priority to a mobility management element, theserving gateway delivers a paging trigger message to the mobilitymanagement element.

Further, after sending the paging trigger message with a servingpriority to the mobility management element, the serving gateway records“information about the sent paging trigger message with a servingpriority”. The paging trigger message is specifically as described inthe foregoing embodiments and is not repeatedly described herein.

In S310, there are multiple manners for the serving gateway to determinewhether the received downlink data packet is a downlink data packet witha serving priority, as described in the foregoing embodiments. Detailsare not repeated herein.

In S310, the “information about the sent paging trigger message with aserving priority” is specifically as described in the foregoingembodiments and is not repeatedly described herein.

When the “information about the sent paging trigger message with aserving priority” is a “flag bit of sent downlink data with a servingpriority”, an example of a specific implementation process of S310 is asdescribed in the foregoing embodiments and is not repeatedly describedherein.

When the “information about the sent paging trigger message with aserving priority” is “information about a priority with a servingpriority”, an example of a specific implementation process of S310 is asdescribed in the foregoing embodiment and is not repeatedly describedherein. When the “information about the sent paging trigger message witha serving priority” is a “flag bit of sent downlink data with a servingpriority” and “information about the sent paging trigger message with aserving priority”, an example of a specific implementation process ofS310 is as described in the foregoing embodiments and is not repeatedlydescribed herein.

In this embodiment, the paging trigger message delivered by the servinggateway to the mobility management element may include information abouta serving priority, where the information about a serving priority mayenable the mobility management element to preferentially page theterminal device. The information about a serving priority in the pagingtrigger message may include: a flag bit with a serving priority and/orinformation about a priority with a serving priority. The contentspecifically included in the information about a serving priority in thepaging trigger message is not limited in this embodiment.

The mobility management element in this embodiment may include an MMEand/or an SGSN. For example, in an application scenario in which the ISRis not activated, the serving gateway may deliver a paging triggermessage to the MME or the SGSN according to an access technology adoptedby the terminal device, whereas in an application scenario in which theISR is activated, the serving gateway may deliver a paging triggermessage to the MME and the SGSN each.

As can be seen from the description in Embodiment 3, after receiving adownlink data packet, the serving gateway in Embodiment 1 may determinewhether it is necessary to deliver a paging trigger message again to themobility management element by determining whether the downlink datapacket is a downlink data packet with a serving priority and whether apaging trigger message has been delivered to the mobility managementelement for the downlink data packet. In this way, even when the servinggateway has been in the state of being forbidden to deliver a pagingtrigger message to the mobility management element to relieve pressureon an air interface, the serving gateway is still capable of deliveringa paging trigger message to the mobility management element for adownlink data packet with a serving priority. The serving gatewaydelivers a paging trigger message to the mobility management element fora downlink data packet with a serving priority. Therefore, pressure onan air interface is basically not increased in this embodiment. In thisway, in this embodiment, a user with an eMPS capability is enabled to bepaged in time while the pressure on the air interface can be reduced,thereby ensuring that the user with the eMPS capability has the priorityto use network resources.

Embodiment 4 provides a service implementation method. The method isdescribed below with reference to FIG. 4 .

As shown in FIG. 4 : S400. A mobility management element receives apaging trigger message of a terminal device sent by a serving gateway.The mobility management element in this embodiment may be an MME or anSGSN.

S410. If the paging trigger message is a paging trigger message with aserving priority and the mobility management element has delivered apaging message with a serving priority to an access network element, themobility management element skips delivering a paging message to theaccess network element.

The access network element may be, for example, a base station (NodeB)or an evolved base station (eNodeB).

S410 may be implemented by using “information about the sent pagingmessage with a serving priority”. A specific example is as follows: Ifthe mobility management element determines that the received pagingtrigger message is a paging trigger message with a priority service witha serving priority and the mobility management element has recorded the“information about the sent paging message with a serving priority”, themobility management element skips delivering a paging message to theaccess network element. The specific name and specific included contentof the paging message are not limited in this embodiment.

In S410, there are multiple manners for the mobility management elementto determine whether the received paging trigger message is a pagingtrigger message with a serving priority. For example, the mobilitymanagement element determines whether the paging trigger message carriesinformation about a serving priority. If the information about a servingpriority is carried, it is determined that the paging trigger message isa paging trigger message with a serving priority. Otherwise, it isdetermined that the paging trigger message is not a paging triggermessage with a serving priority. The specific implementation manner forthe mobility management element to determine whether the received pagingtrigger message is a paging trigger message with a serving priority isnot limited in this embodiment.

The “information about the sent paging message with a serving priority”in S410 may be a “flag bit of the sent paging message with a servingpriority”, “information about a priority with a serving priority”, or a“flag bit of the sent paging message with a serving priority” and“information about a priority with a serving priority”. Certainly, the“information about the sent paging message with a serving priority” mayalso adopt another setting manner. The specific presentation form of the“information about the sent paging message with a serving priority” isnot limited in this embodiment.

The “flag bit of the sent paging message with a serving priority” may bea 1-bit FLAG. For example, when no FLAG is set or a set FLAG is 0, itindicates that no paging message with a serving priority has been sent;when a FLAG is set or a set FLAG is 1, it indicates that a pagingmessage with a serving priority has been sent.

When the “information about the sent paging message with a servingpriority” is a “flag bit of the sent paging message with a servingpriority”, an example of a specific implementation process of S410 is asfollows: The mobility management element determines whether the receivedpaging trigger message is a paging trigger message with a servingpriority and whether the “flag bit of the sent paging message with aserving priority” is set. If the received paging trigger message is apaging trigger message with a serving priority and the “flag bit of thesent paging message with a serving priority” is set, the mobilitymanagement element skips delivering a paging message to the accessnetwork element for the received paging trigger message with a servingpriority. If the mobility management element determines that thereceived paging trigger message is not a paging trigger message with aserving priority, the mobility management element may adopt an existingprocessing manner to perform paging control.

The example of the specific implementation process of S410 may also bedescribed as follows: If the paging trigger message with a servingpriority of the terminal device received by the mobility managementelement is not the first received paging trigger message with a servingpriority, the mobility management element skips delivering a pagingmessage to the access network element.

When the “information about the sent paging trigger message with aserving priority” is “information about a priority with a servingpriority”, an example of a specific implementation process of S410 is asfollows: The mobility management element determines whether the receivedpaging trigger message is a paging trigger message with a servingpriority and whether the “information about a priority with a servingpriority” is set. If the received paging trigger message is a pagingtrigger message with a serving priority and the “information about apriority with a serving priority” is set, the mobility managementelement determines whether the priority of the paging trigger message ishigher than the priority indicated by the set “information about apriority with a serving priority”. If the priority of the paging triggermessage is not higher than the priority indicated by the set“information about a priority with a serving priority”, the mobilitymanagement element skips delivering a paging message to the accessnetwork element for the received paging trigger message with a servingpriority. If the mobility management element determines that thereceived paging trigger message is not a paging trigger message with aserving priority, the mobility management element may adopt an existingprocessing manner to perform paging control.

When the “information about the sent paging trigger message with aserving priority” is a “flag bit of the sent paging message with aserving priority” and “information about a priority with a servingpriority”, an example of a specific implementation process of S410 is asfollows: The mobility management element determines whether the receivedpaging trigger message is a paging trigger message with a servingpriority and whether the “flag bit of the sent paging message with aserving priority” is set. If the received paging trigger message is apaging trigger message with a serving priority and the “flag bit of thesent paging message with a serving priority” is set, the mobilitymanagement element determines whether the priority of the paging triggermessage is higher than the priority indicated by the set “informationabout a priority with a serving priority”. If the priority of the pagingtrigger message is not higher than the priority indicated by the set“information about a priority with a serving priority”, the mobilitymanagement element skips delivering a paging message to the accessnetwork element for the received paging trigger message with a servingpriority. If the mobility management element determines that thereceived paging trigger message is not a paging trigger message with aserving priority, the mobility management element may adopt an existingprocessing manner to perform paging control.

In S410, if the paging trigger message is a paging trigger message witha serving priority and the mobility management element has delivered nopaging message with a serving priority to the access network element,the mobility management element delivers a paging message to the accessnetwork element. Further, after delivering the paging message to theaccess network element, the mobility management element records the“information about the sent paging message with a serving priority”.

As can been seen from the description in Embodiment 4, after receiving apaging trigger message, the mobility management element in Embodiment 4may determine whether to skip delivering a paging message to the accessnetwork element by determining whether the paging trigger message is apaging trigger message with a serving priority and whether a pagingtrigger message with a serving priority has been delivered to the accessnetwork element. In this case, a paging message is delivered to theaccess network element only when the paging trigger message is a pagingtrigger message with a serving priority and no paging trigger messagewith a serving priority has been delivered to the access networkelement. In this way, even when the mobility management element has beenin the state of being forbidden to deliver a paging message to theaccess network element to relieve pressure on an air interface, themobility management element is still capable of delivering a pagingmessage to the access network element for a paging trigger message witha serving priority. The mobility management element delivers a pagingmessage to the access network element for a paging trigger message witha serving priority. Therefore, pressure on an air interface is basicallynot increased in this embodiment. In this way, in this embodiment, auser with an eMPS capability is enabled to be paged in time while thepressure on the air interface can be reduced, thereby ensuring that theuser with the eMPS capability has the priority to use network resources.

Embodiment 5 provides a service implementation method. This embodimentis described in detail below with reference to FIG. 5 .

As shown in FIG. 5 : S500. A mobility management element receives apaging trigger message of a terminal device sent by a serving gateway.The mobility management element in this embodiment may be an MME or anSGSN.

S510. If the paging trigger message is a paging trigger message with aserving priority and no paging message with a serving priority has beendelivered to an access network element, the mobility management elementdelivers a paging message to the access network element.

Further, after sending the paging message with a serving priority to theaccess network element, the mobility management element records“information about the sent paging message with a serving priority”.

A specific example of S510 is as follows: If the mobility managementelement determines that the received paging trigger message is a pagingtrigger message with a serving priority and the mobility managementelement does not record the “information about the sent paging messagewith a serving priority”, the mobility management element delivers apaging message to the access network element and records the“information about the sent paging message with a serving priority”. Thespecific name and specific included content of the paging triggermessage are not limited in this embodiment.

In S510, there are multiple manners for the mobility management elementto determine whether the received paging trigger message is a pagingtrigger message with a serving priority. For example, the mobilitymanagement element determines whether the paging trigger message carriesinformation about a serving priority. If the information about a servingpriority is carried, it is determined that the paging trigger message isa paging trigger message with a serving priority. Otherwise, it isdetermined that the paging trigger message is not a paging triggermessage with a serving priority. The specific implementation manner forthe mobility management element to determine whether the received pagingtrigger message is a paging trigger message with a serving priority isnot limited in this embodiment.

The “information about the sent paging message with a serving priority”in S510 may be a “flag bit of the sent paging message with a servingpriority”, “information about a priority with a serving priority”, or a“flag bit of the sent paging message with a serving priority” and“information about a priority with a serving priority”. Certainly, the“information about the sent paging message with a serving priority” mayalso adopt another setting manner. The specific presentation form of the“information about the sent paging message with a serving priority” isnot limited in this embodiment.

The “flag bit of the sent paging message with a serving priority” may bea 1-bit FLAG. For example, when no FLAG is set or a set FLAG is 0, itindicates that no paging message with a serving priority has been sent;when a FLAG is set or a set FLAG is 1, it indicates that a pagingmessage with a serving priority has been sent.

When the “information about the sent paging message with a servingpriority” is a “flag bit of the sent paging message with a servingpriority”, an example of a specific implementation process of S510 is asfollows: The mobility management element determines whether the receivedpaging trigger message is a paging trigger message with a servingpriority and whether the “flag bit of the sent paging message with aserving priority” is set. If the received paging trigger message is apaging trigger message with a serving priority and the “flag bit of thesent paging message with a serving priority” is not set, the mobilitymanagement element delivers a paging message to the access networkelement and sets the “flag bit of the sent paging message with a servingpriority”. If the mobility management element determines that thereceived paging trigger message is not a paging trigger message with aserving priority, the mobility management element may adopt an existingprocessing manner to perform paging control.

The example of the specific implementation process of S510 may also bedescribed as follows: If the mobility management element receives apaging trigger message with a serving priority of the terminal devicefor the first time, the mobility management element delivers a pagingmessage to the access network element and records the “flag bit of thesent paging message with a serving priority”.

When the “information about the sent paging message with a servingpriority” is “information about a priority with a serving priority”, anexample of a specific implementation process of S510 is as follows: Themobility management element determines whether the received pagingtrigger message is a paging trigger message with a serving priority andwhether the “information about a priority of a serving priority” is set.If the received paging trigger message is a paging trigger message witha serving priority and the “information about a priority of a servingpriority” is set, the mobility management element determines whether thepriority of the paging trigger message is higher than the priorityindicated by the set “information about a priority of a servingpriority”. If the priority of the paging trigger message is higher thanthe priority indicated by the set “information about a priority of aserving priority”, the mobility management element delivers a pagingmessage for the received paging trigger message with a serving priorityand sets the “information about a priority of a serving priority”according to the priority of the paging trigger message. If the receivedpaging trigger message is a paging trigger message with a servingpriority and the “information about a priority of a serving priority” isnot set, the mobility management element delivers a paging message tothe access network element for the received paging trigger message witha serving priority and sets the “information about a priority of aserving priority” according to the priority of the paging triggermessage. If the mobility management element determines that the receivedpaging trigger message is not a paging trigger message with a servingpriority, the mobility management element may adopt an existingprocessing manner to perform paging control.

When the “information about the sent paging message with a servingpriority” is a “flag bit of the sent paging message with a servingpriority” and “information about a priority of a serving priority”, anexample of a specific implementation process of S510 is as follows: Themobility management element determines whether the received pagingtrigger message is a paging trigger message with a serving priority andwhether the “flag bit of the sent paging message with a servingpriority” is set. If the received paging trigger message is a pagingtrigger message with a serving priority and the “flag bit of the sentpaging message with a serving priority” is not set, the mobilitymanagement element delivers a paging message to the access networkelement for the received paging trigger message with a serving priority,sets the “flag bit of the sent paging message with a serving priority”,and sets the “information about a priority of a serving priority”according to the priority of the paging trigger message. If the receivedpaging trigger message is a paging trigger message with a servingpriority and the “flag bit of the sent paging message with a servingpriority” is set, the mobility management element determines whether thepriority of the paging trigger message is higher than the priorityindicated by the set “information about a priority of a servingpriority”. If the priority of the paging trigger message is higher thanthe priority indicated by the set “information about a priority of aserving priority”, the mobility management element delivers a pagingmessage for the received paging trigger message with a serving priorityand sets the “information about a priority of a serving priority”according to the priority of the paging trigger message. If the mobilitymanagement element determines that the received paging trigger messageis not a paging trigger message with a serving priority, the mobilitymanagement element may adopt an existing processing manner to performpaging control.

In this embodiment, the paging message delivered by the mobilitymanagement element may include information about a serving priority,where the information about a serving priority may enable an accessdevice such as a base station to preferentially page the terminaldevice. The information about a serving priority in the paging messagemay include: a flag bit of a serving priority and/or information about apriority of a serving priority. The content specifically included in theinformation about a serving priority in the paging message is notlimited in this embodiment.

As can been seen from the description in Embodiment 5, after receiving apaging trigger message, the mobility management element in Embodiment 5may determine whether it is necessary to deliver a paging message againto the access network element by determining whether the paging triggermessage is a paging trigger message with a serving priority and whethera paging message with a serving priority has been delivered to theaccess network element. In this way, even when the mobility managementelement has been in the state of being forbidden to deliver a pagingmessage to the access network element to relieve pressure on an airinterface, the mobility management element is still capable ofdelivering a paging message to the access network element for a pagingtrigger message with a serving priority. The mobility management elementdelivers a paging message to the access network element for a pagingtrigger message with a serving priority. Therefore, pressure on an airinterface is basically not increased in this embodiment. In this way, inthis embodiment, a user with an eMPS capability is enabled to be pagedin time while the pressure on the air interface can be reduced, therebyensuring that the user with the eMPS capability has the priority to usenetwork resources.

Embodiment 6 provides a service implementation method when the ISR isnot activated. The process of the method is shown in FIG. 6 .

As shown in FIG. 6 : S1. A P-GW sends a downlink data packet to an S-GW,where the downlink data packet may be a user-plane data packet orcontrol signaling.

S2. The S-GW determines that the downlink data packet is a downlink datapacket with a serving priority and that no downlink data notificationhas been sent for a downlink data packet with a serving priority.Therefore, the S-GW sends a paging trigger message such as a downlinkdata notification message or control signaling to an MME. The S-GWrecords “information about the sent paging trigger message with aserving priority”. For example, the S-GW records at least one of: a“flag bit of sent downlink data with a serving priority” and“information about a priority of a serving priority”.

The “information about the sent paging trigger message with a servingpriority” recorded by the S-GW is used for the S-GW to determine, afterreceiving a downlink data packet the next time, whether a downlink datanotification message has been sent for a downlink data packet with aserving priority. For example, if the S-GW receives another downlinkdata packet with a serving priority of a UE, the S-GW may determine,according to the recorded information, to skip sending a downlink datanotification message to the MME. For another example, if the S-GWreceives another downlink data packet with a serving priority of the UE,the S-GW may perform comparison of priorities of serving prioritiesaccording to recorded information. If the priority of the receiveddownlink data packet of the UE with a serving priority is higher thanthe priority of a serving priority in the recorded information, the S-GWsends a downlink data notification message to the MME. Otherwise, theS-GW skips sending a downlink data notification message to the MME.

It should be noted that when the S-GW determines that the downlink datapacket is a downlink data packet with a serving priority and that nodownlink data notification message has been sent for a downlink datapacket with a serving priority and even when a delay timer in the S-GWis still operating, the S-GW will ignore the operating of the timer andsend a downlink data notification message to the MME.

Alternatively, the paging trigger message delivered by the S-GW to theMME in S2 may include information about a serving priority, for example,the downlink data notification message includes a Priority Indication(that is, the serving-priority flag bit in the foregoing embodiments)and/or information about a priority of a serving priority (which mayalso be named information about a level of a serving priority). Theinformation about a serving priority in the downlink data notificationmessage may enable the MME to preferentially perform paging processingfor the downlink data notification. For example, when MME resources arelimited, paging processing is still performed for the downlink datanotification message. The specific presentation form of the informationabout a serving priority is not limited in this embodiment.

In this embodiment, it is set that the downlink data packet received bythe S-GW in S2 is a user-plane data packet. In this case, the S-GW maydetermine a bearer corresponding to the user-plane data packet anddetermine whether the downlink data packet is a downlink data packetwith a serving priority according to bearer information (such as QoS ofthe bearer) of the bearer, where the bearer information is stored by theS-GW. For example, the S-GW may determine whether the downlink datapacket is a downlink data packet with a serving priority according tothe ARP parameter or the like in the QOS of the bearer.

If the downlink data packet received by the S-GW in S2 is replaced withcontrol signaling (such as an Update Bearer Request (update bearerrequest)), the S-GW may determine whether the downlink data packet is adownlink data packet with a serving priority according to bearerinformation (such as QOS of the bearer) included in the controlsignaling. A specific example is as follows: The S-GW determines whetherthe control signaling is signaling for improving the priority of the UEbearer according to a QOS parameter in a Bearer context (bearer context)information element in the update bearer request. If yes, the S-GWdetermines that the update bearer request is control signaling with aserving priority. Otherwise, the S-GW determines that the update bearerrequest is not control signaling with a serving priority.

S2b. After receiving the downlink data notification, the MME returns aDownlink Data Notification Ack (downlink data notificationacknowledgment) message to the S-GW. Alternatively, if the downlink datanotification message received by the MME includes the information abouta serving priority, the downlink data notification acknowledgmentmessage returned by the MME may also include the information about aserving priority. For example, the downlink data notificationacknowledgment message includes at least one of: the Priority Indicationand the information about the priority of a serving priority.

If in S2, the S-GW sends a paging trigger message to the MME but theS-GW does not perform the operation of recording the “information aboutthe sent paging trigger message with a serving priority”, the S-GW mayperform the operation of recording the “information about the sentpaging trigger message with a serving priority” after receiving thedownlink data notification acknowledgment message returned by the MME.

S3. After receiving the downlink data notification message, the MMEsends a paging message to an eNodeB. Specifically, after receiving adownlink data notification message for the first time, the MME sends apaging message to the eNodeB. After receiving a downlink datanotification message again and determining that the downlink datanotification message carries the information about a serving priority,the MME sends a paging message again to the eNodeB and records theinformation about a serving priority. Alternatively, if the downlinkdata notification message received by the MME includes the informationabout a serving priority, the MME may preferentially send a pagingmessage to the eNodeB. In addition, the paging message sent by the MMEto the eNodeB may include the information about a serving priority.

S4. After receiving the paging message, the eNodeB sends a pagingmessage to the UE, so as to page the UE.

S5. After receiving the paging message, the UE initiates a servicerequest procedure and establishes an air interface and a bearer of an S1connection.

S6. The MME sends a Modify Bearer Request (modify bearer request)message to the S-GW and notifies the address of the bearer of the UE inthe eNodeB to the S-GW. Alternatively, the modify bearer request messagesent by the MME to the S-GW includes the information about a servingpriority.

Alternatively, this embodiment may include S7 and S8.

S7. The S-GW sends a modify bearer request message to the P-GW.

S8. The P-GW returns a modify bearer response message to the S-GW.

S9. The S-GW sends a modify bearer response message to the MME.

S5 to S9 are a service request processing procedure. In this embodiment,subsequent steps of service implementation are omitted.

In Embodiment 6, after receiving the downlink data packet, the S-GW maynot determine whether to deliver a paging trigger message and insteaddirectly delivers a paging trigger message to the MME according to thereceived downlink data packet.

As can be seen from the description in Embodiment 6, after receiving adownlink data packet, the S-GW in Embodiment 6 may determine whether itis necessary to deliver a paging trigger message again to the MME bydetermining whether the downlink data packet is a downlink data packetwith a serving priority and whether a paging trigger message has beendelivered to the MME for the downlink data packet. In this way, evenwhen the S-GW has been in the state of being forbidden to deliver apaging trigger message to the MME to relieve pressure on an airinterface, the S-GW is still capable of delivering a paging triggermessage to the MME for a downlink data packet with a serving priority. Apaging trigger message is delivered to the MME for a downlink datapacket with a serving priority. Therefore, pressure on an air interfaceis basically not increased in this embodiment. In this way, in thisembodiment, a user with an eMPS capability is enabled to be paged intime while the pressure on the air interface can be reduced, therebyensuring that the user with the eMPS capability has the priority to usenetwork resources.

Embodiment 7 provides a service implementation method when the ISR isactivated. The process of the method is shown in FIG. 7A.

A common downlink data packet (not a downlink data packet with a servingpriority) may arrive at an S-GW before a downlink data packet with aserving priority. A specific example is shown in FIG. 7A.

In FIG. 7A, after an UE accesses a network, the network provides abearer for the UE, thereby providing a transmission service for auser-plane data packet of the UE.

As shown in FIG. 7A: S1. After receiving a user-plane data packet of theUE, an Application Function (application function, AF) may send theuser-plane data packet to the UE through the bearer. The AF may furthersend a notification message to a PCRF to notify the PCRF of an attribute(that is, an attribute of a service stream, such as a type of theservice stream) of the user-plane data packet.

S2. After receiving the notification message, the PCRF determines,according to the attribute information of the service stream, whether itis necessary to initiate an IP-CAN session modify process. If it isnecessary to perform the initiation, the PCRF triggers a PDN-GW/PCEF tosend control signaling such as an Update Bearer Request message or aCreate Bearer Request (create bearer request) message to the S-GW. Inthis way, the QOS of the bearer of the UE can be improved.

The user-plane data packet in FIG. 7A may arrive at the S-GW before thecontrol signaling. Therefore, the S-GW may deliver a downlink datanotification message for the user-plane data packet first. In the priorart, the ISR is activated. Therefore, the S-GW will not deliver adownlink data notification message again for the control signalingbefore receiving a response message of the UE. As a result, the UE willnot be paged preferentially.

As shown in FIG. 7B: S1. A P-GW sends a downlink data packet to an S-GW,where the downlink data packet may be a user-plane data packet orcontrol signaling.

S2. The S-GW caches the received downlink data packet and delivers adownlink data notification message to an MME and an SGSN each. If theS-GW receives a downlink data packet of a UE again after delivering thedownlink data notification message and before receiving a responsemessage of the UE and the downlink data packet is a downlink data packetwith a serving priority, the S-GW continues to deliver a downlink datanotification message to the MME and the SGSN each, where the downlinkdata notification message includes information about a serving priority.The S-GW records “information about the sent paging trigger message witha serving priority”. For example, a flag bit of a “notificationindication of sent downlink data with a serving priority” is set. Foranother example, a flag bit of a “notification indication of sentpreferential downlink data”, information about a priority of a servingpriority, and the like are set.

If the S-GW receives a downlink data packet with a serving priorityagain after setting the “information about the sent paging triggermessage with a serving priority, the S-GW may skip sending apreferential downlink data notification message.

S3a. After receiving the downlink data notification message, the MMEsends a paging message to an access network element such as an eNodeB.Specifically, after receiving a downlink data notification message forthe first time, the MME sends a paging message to the eNodeB. Afterreceiving a downlink data notification message again and determiningthat the downlink data notification message carries the informationabout a serving priority, the MME sends a paging message again to theeNodeB and records the information about a serving priority.Alternatively, if the downlink data notification message received by theMME includes the information about a serving priority, the MME maypreferentially send a paging message to the access network element. Inaddition, the paging message sent by the MME may include the informationabout a serving priority.

S3b. After receiving the downlink data notification message, the SGSNsends a paging message to an access network element such as an RNC.Specifically, after receiving a downlink data notification message forthe first time, the SGSN sends a paging message to the RNC. Afterreceiving a downlink data notification message again and determiningthat the downlink data notification message carries the informationabout a serving priority, the SGSN sends a paging message again to theRNC and records the information about a serving priority. Alternatively,if the downlink data notification message received by the SGSN includesthe information about a serving priority, the SGSN may preferentiallysend a paging message to the access network element. In addition, thepaging message sent by the SGSN may include the information about aserving priority.

S4a. After receiving the paging message, the access network elementeNodeB sends a paging message to the UE, so as to page the UE.

S4b. After receiving the paging message, the RNC sends a paging messageto the UE, so as to page the UE.

In this embodiment, the access network element may also adopt theprocessing manner of the S-GW. That is, if the access network elementdetermines that the received paging message is a paging message with aserving priority and determines that a paging message has been deliveredto the UE, the mobility management element may deliver a paging messageto the UE again and store “information about the sent paging messagewith a serving priority”. For the specific implementation process forthe access network element to deliver a paging message, reference may bemade to a specific implementation process of a serving gateway describedin each of the foregoing embodiments. Details are not repeated herein.

S5. After receiving the paging message, the UE initiates a servicerequest procedure and establishes an air interface and a bearer of an S1connection.

S6. After receiving a response message of the UE for the paging message,the S-GW stops paging. That is, even when receiving a downlink datapacket with a higher priority, the S-GW does not send a downlink datanotification message to the MME and the SGSN.

In Embodiment 7, after receiving the downlink data packet, the S-GW maynot determine whether to deliver a paging trigger message to the MME andthe SGSN and instead directly delivers a paging trigger message to theMME and the SGSN according to the received downlink data packet.

As can be seen from the description in Embodiment 7, after receiving adownlink data packet, the S-GW in Embodiment 7 may determine whether itis necessary to deliver a paging trigger message again to the MME andthe SGSN by determining whether the downlink data packet is a downlinkdata packet with a serving priority and whether a paging trigger messagehas been delivered to the MME and the SGSN for the downlink data packet.In this way, even when the S-GW has been in the state of being forbiddento deliver a paging trigger message to the MME and the SGSN to relievepressure on an air interface, the serving gateway is still capable ofdelivering a paging trigger message to the MME and the SGSN for adownlink data packet with a serving priority. A paging trigger messageis delivered to the MME and the SGSN for a downlink data packet with aserving priority. Therefore, pressure on an air interface is basicallynot increased in this embodiment. In this way, in this embodiment, auser with an eMPS capability is enabled to be paged in time while thepressure on the air interface can be reduced, thereby ensuring that theuser with the eMPS capability has the priority to use network resources.

Embodiment 8 provides a service implementation apparatus. The apparatusis a serving gateway. The apparatus is described below with reference toFIG. 8 .

The service implementation apparatus shown in FIG. 8 includes a firstreceiving module 800 and a first control module 810.

The first receiving module 800 is configured to receive a downlink datapacket of a terminal device sent by a packet data network gateway. Thedownlink data packet received by the first receiving module 800 may be auser-plane data packet or control signaling. The control signaling maybe, for example, a create bearer request, a create dedicated bearerrequest, or an update bearer request.

The first control module 810 is configured to skip delivering a pagingtrigger message to a mobility management element if the downlink datapacket received by the first receiving module 800 is a downlink datapacket with a serving priority and the service implementation apparatushas delivered a paging trigger message with a serving priority to themobility management element. The paging trigger message is used toenable the mobility management element to page the terminal device.

The first control module 810 may determine whether a paging triggermessage with a serving priority has been delivered according to“information about the sent paging trigger message with a servingpriority”. For example, if the first control module 810 determines thatthe downlink data packet received by the first receiving module 800 is adownlink data packet with a serving priority and the serving gateway hasrecorded the “information about the sent paging trigger message with aserving priority”, the first control module 810 skips delivering apaging trigger message to the mobility management element. The pagingtrigger message may specifically be a downlink data notification messageor control signaling.

There are multiple manners for the first control module 810 to determinewhether the downlink data packet received by the first receiving module800 is a downlink data packet with a serving priority, as described inthe foregoing method embodiments. Details are not repeated herein.

The “information about the sent paging trigger message with a servingpriority” recorded by the serving gateway may be a “flag bit of sentdownlink data with a serving priority”, “information about a priority ofa serving priority”, or a “flag bit of sent downlink data with a servingpriority” and “information about a priority of a serving priority”.Certainly, the “information about the sent paging trigger message with aserving priority” may also adopt another setting manner.

When the “information about the sent paging trigger message with aserving priority” is a “flag bit of sent downlink data with a servingpriority”, “information about a priority of a serving priority”, or a“flag bit of sent downlink data with a serving priority” and“information about a priority of a serving priority”, operationsspecifically performed by the first control module 810 are as describedin the foregoing method embodiments. Details are not repeated herein.

As can be seen from the description in Embodiment 8, after the firstreceiving module 800 receives a downlink data packet, the first controlmodule 810 in Embodiment 8 may determine whether to skip delivering apaging trigger message to the mobility management element by determiningwhether the downlink data packet is a downlink data packet with aserving priority and whether a paging trigger message with a servingpriority has been delivered to the mobility management element. In thiscase, the first control module 810 delivers a paging trigger message tothe mobility management element only when the downlink data packet is adownlink data packet with a serving priority and no paging triggermessage with a serving priority has been delivered to the mobilitymanagement element. In this way, even when the serving gateway has beenin the state of being forbidden to deliver a paging trigger message tothe mobility management element to relieve pressure on an air interface,the first control module 810 is still capable of delivering a pagingtrigger message to the mobility management element for a downlink datapacket with a serving priority. The first control module 810 delivers apaging trigger message to the mobility management element for a downlinkdata packet with a serving priority. Therefore, pressure on an airinterface is basically not increased in this embodiment. In this way, inthis embodiment, a user with an eMPS capability is enabled to be pagedin time while the pressure on the air interface can be reduced, therebyensuring that the user with the eMPS capability has the priority to usenetwork resources.

Embodiment 9 provides a service implementation apparatus. The apparatusis a serving gateway. The apparatus is described below with reference toFIG. 9 .

The service implementation apparatus shown in FIG. 9 includes a firstreceiving module 900 and a first control module 910. Alternatively, theapparatus may further include a first recording module 920.

The first receiving module 900 is configured to receive a downlink datapacket of a terminal device sent by a packet data network gateway. Thedownlink data packet received by the first receiving module 900 may be auser-plane data packet or control signaling. The control signaling maybe, for example, a create bearer request, a create dedicated bearerrequest, or an update bearer request.

The first control module 910 is configured to deliver a paging triggermessage to a mobility management element if the downlink data packetreceived by the first receiving module 900 is a downlink data packetwith a serving priority and the service implementation apparatus hasdelivered no paging trigger message with a serving priority. The pagingtrigger message is used to enable the mobility management element topage the terminal device.

The first recording module 920 is configured to record “informationabout the sent paging trigger message with a serving priority” after thefirst control module 910 sends the paging trigger message to themobility management element.

The first control module 910 may determine whether a paging triggermessage with a serving priority has been delivered according to the“information about the sent paging trigger message with a servingpriority” recorded by the first recording module 920. For example, ifthe first control module 910 determines that the downlink data packetreceived by the first receiving module 900 is a downlink data packetwith a serving priority and the first recording module 920 has recordedno “information about the sent paging trigger message with a servingpriority”, the first control module 910 delivers a paging triggermessage to the mobility management element. The paging trigger messagedelivered by the first control module 910 to the mobility managementelement may specifically be a downlink data notification message,control signaling, or the like.

There are multiple manners for the first control module 910 to determinewhether the downlink data packet received by the first receiving module900 is a downlink data packet with a serving priority, as described inthe foregoing method embodiments. Details are not repeated herein.

The “information about the sent paging trigger message with a servingpriority” recorded by the first recording module 920 may be a “flag bitof sent downlink data with a serving priority”, “information about apriority of a serving priority”, or a “flag bit of sent downlink datawith a serving priority” and “information about a priority of a servingpriority”. Certainly, the “information about the sent paging triggermessage with a serving priority” may also adopt another setting manner.

When the “information about the sent paging trigger message with aserving priority” is a “flag bit of sent downlink data with a servingpriority”, “information about a priority of a serving priority”, or a“flag bit of sent downlink data with a serving priority” and“information about a priority of a serving priority”, operationsspecifically performed by the first control module 910 are as describedin the foregoing method embodiments. Details are not repeated herein.

In this embodiment, the paging trigger message delivered by the firstcontrol module 910 to the mobility management element may includeinformation about a serving priority, where the information about aserving priority may enable the mobility management element topreferentially page the terminal device. The information about a servingpriority in the paging trigger message may include: a flag bit of aserving priority and/or information about a priority of a servingpriority.

The mobility management element in this embodiment may include an MMEand/or an SGSN. For example, in an application scenario in which the ISRis not activated, the first control module 910 may deliver a pagingtrigger message to the MME or the SGSN according to an access technologyadopted by the terminal device, whereas in an application scenario inwhich the ISR is activated, the first control module 910 may deliver apaging trigger message to the MME and the SGSN each.

As can be seen from the description in Embodiment 9, after the firstreceiving module 900 receives a downlink data packet, the first controlmodule 910 in Embodiment 9 may determine whether it is necessary todeliver a paging trigger message again to the mobility managementelement by determining whether the downlink data packet is a downlinkdata packet with a serving priority and whether a paging trigger messagehas been delivered to the mobility management element for the downlinkdata packet. In this way, even when the serving gateway has been in thestate of being forbidden to deliver a paging trigger message to themobility management element to relieve pressure on an air interface, thefirst control module 910 is still capable of delivering a paging triggermessage to the mobility management element for a downlink data packetwith a serving priority. The first control module 910 delivers a pagingtrigger message to the mobility management element for a downlink datapacket with a serving priority. Therefore, pressure on an air interfaceis basically not increased in this embodiment. In this way, in thisembodiment, a user with an eMPS capability is enabled to be paged intime while the pressure on the air interface can be reduced, therebyensuring that the user with the eMPS capability has the priority to usenetwork resources.

Embodiment 10 provides a service implementation apparatus. The apparatusis a mobility management element and the mobility management element isan MME, an SGSN, or the like. The apparatus is described below withreference to FIG. 10 .

The service implementation apparatus shown in FIG. 10 includes a secondreceiving module 1000 and a second control module 1010.

The second receiving module 1000 is configured to receive a pagingtrigger message of a terminal device sent by a serving gateway.

The second control module 1010 is configured to skip delivering a pagingmessage to an access network element if the paging trigger messagereceived by the second receiving module 1000 is a paging trigger messagewith a serving priority and the service implementation apparatus hasdelivered a paging message with a serving priority to the access networkelement.

The second control module 1010 may determine, according to “informationabout the sent paging message with a serving priority”, whether a pagingmessage with a serving priority has been delivered to the access networkelement. For example, if the second control module 1010 determines thatthe paging trigger message received by the second receiving module 1000is a paging trigger message with a serving priority and the mobilitymanagement element has recorded the “information about the sent pagingmessage with a serving priority”, the second control module 1010 skipsdelivering a paging message to the access network element. The specificname and specific included content of the paging message are not limitedin this embodiment.

There are multiple manners for the second control module 1010 todetermine whether the paging trigger message received by the secondreceiving module 1000 is a paging trigger message with a servingpriority, as described in the foregoing method embodiments. Details arenot repeated herein.

The “information about the sent paging message with a serving priority”may be a “flag bit of the sent paging message with a serving priority”,“information about a priority of a serving priority”, or a “flag bit ofthe sent paging message with a serving priority” and “information abouta priority of a serving priority”. Certainly, the “information about thesent paging message with a serving priority” may also adopt anothersetting manner. The specific presentation form of the “information aboutthe sent paging message with a serving priority” is not limited in thisembodiment.

When the “information about the sent paging message with a servingpriority” is a “flag bit of the sent paging message with a servingpriority”, “information about a priority of a serving priority”, or a“flag bit of the sent paging message with a serving priority” and“information about a priority of a serving priority”, operationsspecifically performed by the second control module 1010 are asdescribed in the foregoing method embodiments. Details are not repeatedherein.

As can be seen from the description in Embodiment 10, after the secondreceiving module 1000 receives a paging trigger message, the secondcontrol module 1010 in Embodiment 10 may determine whether to skipdelivering a paging message again to the access network element bydetermining whether the paging trigger message is a paging triggermessage with a serving priority and whether the service implementationapparatus has delivered a paging message with a serving priority to theaccess network element. In this case, the second control module 1010delivers a paging message to the access network element only when thepaging trigger message is a paging trigger message with a servingpriority and the service implementation apparatus has delivered nopaging trigger message with a serving priority to the access networkelement. In this way, even when the mobility management element has beenin the state of being forbidden to deliver a paging message to theaccess network element to relieve pressure on an air interface, themobility management element is still capable of delivering a pagingmessage to the access network element for a paging trigger message witha serving priority. The mobility management element delivers a pagingmessage to the access network element for a paging trigger message witha serving priority. Therefore, pressure on an air interface is basicallynot increased in this embodiment. In this way, in this embodiment, auser with an eMPS capability is enabled to be paged in time while thepressure on the air interface can be reduced, thereby ensuring that theuser with the eMPS capability has the priority to use network resources.

Embodiment 11 provides a service implementation apparatus. The apparatusis a mobility management element and the mobility management element isan MME, an SGSN, or the like. The apparatus is described below withreference to FIG. 11 .

The service implementation apparatus shown in FIG. 11 includes a secondreceiving module 1100 and a second control module 1110. Alternatively,the apparatus may further include a second recording module 1120.

The second receiving module 1100 is configured to receive a pagingtrigger message of a terminal device sent by a serving gateway.

The second control module 1110 is configured to deliver a paging messageto an access network element if the paging trigger message received bythe second receiving module 1100 is a paging trigger message with aserving priority and the service implementation apparatus has sent nopaging message with a serving priority to the access network element.

The second recording module 1120 is configured to record “informationabout the sent paging message with a serving priority” after the secondcontrol module 1110 sends the paging message to the access networkelement.

The second control module 1110 may determine, according to the“information about the sent paging message with a serving priority”recorded by the second recording module 1120, whether a paging messagewith a serving priority has been delivered to the access networkelement. For example, if the second control module 1110 determines thatthe paging trigger message received by the second receiving module 1100is a paging trigger message with a serving priority and the secondrecording module 1120 has recorded no “information about the sent pagingmessage with a serving priority”, the second control module 1110delivers a paging message to the access network element. The specificname and specific included content of the paging message are not limitedin this embodiment.

There are multiple manners for the second control module 1110 todetermine whether the paging trigger message received by the secondreceiving module 1100 is a paging trigger message with a servingpriority, as described in the foregoing method embodiments. Details arenot repeated herein.

The “information about the sent paging message with a serving priority”recorded by the second recording module 1120 may be a “flag bit of thesent paging message with a serving priority”, “information about apriority of a serving priority”, or a “flag bit of the sent pagingmessage with a serving priority” and “information about a priority of aserving priority”. Certainly, the “information about the sent pagingmessage with a serving priority” may also adopt another setting manner.The specific presentation form of the “information about the sent pagingmessage with a serving priority” is not limited in this embodiment.

When the “information about the sent paging message with a servingpriority” recorded by the second recording module 1120 is a “flag bit ofthe sent paging message with a serving priority”, “information about apriority of a serving priority”, or a “flag bit of the sent pagingmessage with a serving priority” and “information about a priority of aserving priority”, operations specifically performed by the secondcontrol module 1110 are as described in the foregoing methodembodiments. Details are not repeated herein.

In this embodiment, the paging message delivered by the second controlmodule 1110 to the access network element may include information abouta serving priority, where the information about a serving priority mayenable an access device such as a base station to preferentially pagethe terminal device. The information about a serving priority in thepaging message may include: a flag bit of a serving priority and/orinformation about a priority of a serving priority. The contentspecifically included in the information about a serving priority in thepaging message is not limited in this embodiment.

As can been seen from the description in Embodiment 11, after the secondreceiving module 1100 receives a paging trigger message, the secondcontrol module 1110 in Embodiment 11 may determine whether it isnecessary to deliver a paging message again to the access networkelement by determining whether the paging trigger message is a pagingtrigger message with a serving priority and whether a paging messagewith a serving priority has been delivered to the access networkelement. In this way, even when the mobility management element has beenin the state of being forbidden to deliver a paging message to theaccess network element to relieve pressure on an air interface, thesecond control module 1110 is still capable of delivering a pagingmessage to the access network element for a paging trigger message witha serving priority. The second control module 1110 delivers a pagingmessage to the access network element for a paging trigger message witha serving priority. Therefore, pressure on an air interface is basicallynot increased in this embodiment. In this way, in this embodiment, auser with an eMPS capability is enabled to be paged in time while thepressure on the air interface can be reduced, thereby ensuring that theuser with the eMPS capability has the priority to use network resources.

Embodiment 12 provides a service implementation system. This embodimentis described below with reference to FIG. 12 .

The system shown in FIG. 12 includes a mobility management element 1210connected to a serving gateway 1200. Alternatively, the system may alsoinclude the serving gateway 1200. The mobility management element is,for example, an MME and/or an SGSN. Although FIG. 12 shows only onemobility management element 1210, there may be multiple mobilitymanagement elements 1210.

The serving gateway 1200 is configured to receive a downlink data packetof a terminal device sent by a packet data network gateway and deliver apaging trigger message to the mobility management element 1210.Alternatively, if the downlink data packet received by the servinggateway 1200 is a downlink data packet with a serving priority and theserving gateway 1200 has delivered a paging trigger message with aserving priority to the mobility management element 1210, the servinggateway 1200 skips delivering a paging trigger message to the mobilitymanagement element 1210. If the downlink data packet received by theserving gateway 1200 is a downlink data packet with a serving priorityand the serving gateway 1200 has delivered no paging trigger messagewith a serving priority to the mobility management element 1210, theserving gateway 1200 delivers a paging trigger message to the mobilitymanagement element 1210. Alternatively, after sending the paging triggermessage, the serving gateway 1200 records “information about the sentpaging trigger message with a serving priority”.

The mobility management element 1210 is configured to receive a pagingtrigger message of the terminal device sent by the serving gateway 1200,and if it is determined that the paging trigger message is a pagingtrigger message with a serving priority and a paging message with aserving priority has been delivered to an access network element, skipdelivering a paging message to the access network element; or if it isdetermined that the paging trigger message is a paging trigger messagewith a serving priority and no paging message with a serving priorityhas been delivered to an access network element, deliver a pagingmessage to the access network element. Alternatively, after sending thepaging message to the access network element, the mobility managementelement 1210 records “information about the sent paging message with aserving priority”.

Specifically performed operations, structures, and the like of theserving gateway 1200 and the mobility management element 1210 are asdescribed in the foregoing method and apparatus embodiments. Details arenot repeated herein.

Through the description of the preceding embodiments, persons skilled inthe art may clearly understand that the present invention may beimplemented by software plus a necessary hardware platform, anddefinitely may also be implemented by hardware, but in most cases, theformer is a preferred implementation manner. Based on suchunderstanding, part of or all of the technical solutions of the presentinvention that makes contributions to the prior art may be embodied in aform of a software product. The software product may be used to executethe foregoing method process. The computer software product may bestored in a readable storage medium, for example, a ROM/RAM, a magneticdisk, or an optical disk, and includes several instructions used toinstruct a computer device (for example, a personal computer, a server,or a network device, and so on) to execute the method described in theembodiments of the present invention or a certain part of theembodiments.

Although the present invention is described through embodiments, personsof ordinary skill in the art should know that, a lot of variations andchanges of the present invention without departing from the spirit ofthe present invention should be covered by the claims of the applicationdocument of the present invention.

What is claimed is:
 1. A service implementation method, comprising: receiving, by a serving gateway, a first data packet of a terminal device sent by a packet data network gateway; determining, by the serving gateway, that the first data packet is with a second priority according to information of a bearer corresponding to the first data packet, wherein the information comprises an allocation and retention priority (ARP) parameter; determining, by the serving gateway, that the data packet is a data packet with a second priority and the second priority is higher than a first priority, wherein the first priority is a priority of in a first downlink data notification message sent to a mobility management entity(MME), wherein the first downlink data notification message is for notifying coming of a second data packet and is for triggering paging the terminal; in response to the second priority is higher than the first priority, sending, by the serving gateway, a second downlink data notification message with the second priority to the MME, wherein the determining that the data packet is with the second priority is according to information of a bearer corresponding to the data packetmobility management entity, wherein the second downlink data notification message is for notifying coming of the first data packet and is for triggering paging the terminal.
 2. The method according to claim 1, further comprising: recording, by the serving gateway, the second priority.
 3. The method according to claim 1, wherein the first priority is recorded by the serving gateway.
 4. The method according to claim 1, wherein before the receiving, the method further comprises: sending, by the serving gateway, the first downlink data notification message with the first priority to the MME mobility management entity.
 5. The method according to claim 1, wherein a delay timer in the serving gateway is running.
 6. The method according to claim 1, wherein the data packet comprises a user-plane data packet.
 7. A serving gateway, comprising: a receiver, configured to receive a first data packet of a terminal device sent by a packet data network gateway; a processor, coupled to the receiver, configured to determine that the first data packet is with a second priority according to information of a bearer corresponding to the first data packet, and determine that the data packet is a data packet with a second priority and the second priority is higher than a first priority, wherein the first priority is a priority of in a first downlink data notification message sent to a (MME) mobility management entity, wherein the first downlink data notification message is for notifying coming of a second data packet and is for triggering paging the terminal, and wherein the information comprises an allocation and retention priority (ARP) parameter; a transmitter, coupled to the processor, configured to send a second downlink data notification message with the second priority to the MME, mobility management entity in response to the second priority is higher than the first priority, wherein the second downlink data notification message is for notifying coming of the first data packet and is for triggering paging the terminal wherein the processor determines the data packet is with the second priority according to information of a bearer corresponding to the data packet.
 8. The serving gateway according to claim 7, wherein the processor is further configured to record the second priority.
 9. The serving gateway according to claim 7, wherein the first priority is recorded by the serving gateway.
 10. The serving gateway according to claim 7, wherein the transmitter is further configured to send the first downlink data notification message with the first priority to the MME mobility management entity.
 11. The serving gateway according to claim 7, wherein a delay timer in the serving gateway is running.
 12. The serving gateway according to claim 7, wherein the data packet comprises a user-plane data packet.
 13. A service implementation method, comprising: receiving, by a mobility management element, a first paging trigger message of a terminal from a serving gateway, wherein the first paging trigger message comprises a first priority; sending, by the mobility management element, a first paging message to a base station in response to the first paging trigger message; receiving, by the mobility management element, a second paging trigger message of the terminal from the serving gateway before the mobility management element receives a response of the first paging message, wherein the second paging trigger message comprises a second priority; determining, by the mobility management element, whether the second priority comprised in the second paging trigger message is higher than the first priority comprised in the first paging trigger message; and sending, by the mobility management element, a second paging message to the base station, if the second priority is higher than the first priority; and skipping, by the mobility management element, sending the second paging message to the base station if the second priority is not higher than the first priority.
 14. The method according to claim 13, wherein the second paging message comprises the second priority.
 15. The method according to claim 14, wherein the second paging trigger message is a downlink data notification message.
 16. The method according to claim 15, further comprising: paging preferentially, by the base station, the terminal according to the second priority comprised in the second paging message.
 17. The method according to claim 15, further comprising: sending, by the serving gateway, the first paging trigger message of the terminal to the mobility management element.
 18. A mobility management element, comprising: a processor; and a computer readable storage medium storing one or more programs for execution by the processor, the one or more programs including instructions to: receive a first paging trigger message of a terminal from a serving gateway, wherein the first paging trigger message comprises a first priority; send a first paging message to a base station in response to the first paging trigger message; receive a second paging trigger message of the terminal from the serving gateway before the mobility management element receives a response of the first paging message, wherein the second paging trigger message comprises a second priority; determine whether the second priority comprised in the second paging trigger message is higher than the first priority comprised in the first paging trigger message; and send a second paging message to the base station if the second priority is higher than the first priority; and skip sending the second paging message to the base station if the second priority is not higher than the first priority.
 19. The mobility management element according to claim 18, wherein the second paging message comprises the second priority.
 20. The mobility management element according to claim 19, wherein the second paging trigger message is a downlink data notification message.
 21. A communication system, comprising: a mobility management element, configured to: receive a first paging trigger message of a terminal from a serving gateway, wherein the first paging trigger message comprises a first priority; send a first paging message to a base station in response to the first paging trigger message; receive a second paging trigger message of the terminal from the serving gateway before the mobility management element receives a response of the first paging message, wherein the second paging trigger message comprises a second priority; determine whether the second priority comprised in the second paging trigger message is higher than the first priority comprised in the first paging trigger message; and send a second paging message to the base station, if the second priority is higher than the first priority; wherein the second paging message comprises the second priority; and skip sending the second paging message to the base station if the second priority is not higher than the first priority; the base station, configured to: page preferentially the terminal according to the second priority comprised in the second paging message after receiving the second paging message from the mobility management element.
 22. The method according to claim 2, further comprising: receiving, by the serving gateway, another data packet of the terminal device from the packet data network gateway; and skipping, by the serving gateway, based on a record of the second priority on the serving gateway, sending another downlink data notification message to the mobility management entity in response to the another data packet.
 23. The serving gateway according to claim 8, wherein the processor is further configured to: receive another data packet of the terminal device from the packet data network gateway; and skip, based on a record of the second priority on the serving gateway, sending another downlink data notification message to the mobility management entity in response to the another data packet.
 24. The method according to claim 13, further comprising: receiving, by the mobility management element, a third paging trigger message of a terminal from a serving gateway, wherein the third paging trigger message comprises a third priority; sending, by the mobility management element, a third paging message to a base station in response to the third paging trigger message; receiving, by the mobility management element, a fourth paging trigger message of the terminal from the serving gateway before the mobility management element receives a response of the third paging message, wherein the fourth paging trigger message comprises a fourth priority; determining, by the mobility management element, whether the fourth priority comprised in the fourth paging trigger message is higher than the third priority comprised in the third paging trigger message; and skipping, by the mobility management element, sending a fourth paging message to the base station, in response to determining that the fourth priority is not higher than the third priority. 